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HAPTER 



2 



Lacrimal Drainage 
System 



t INTRODUCTION 44 

Applied anatomy 44 
Applied physiology 44 
Causes of watering 45 

• EVALUATION OF THE WATERING 
EYE 45 

• OBSTRUCTION OF LACRIMAL 
DRAINAGE 48 

Acquired obstruction 48 
Congenital obstruction 50 
Principles of lacrimal surgery 52 

• INFECTIONS OF LACRIMAL 
PASSAGES 53 

Chronic canaliculitis 53 
Dacryocystitis 54 



43 



44 



Clinical Ophthalmology 




Introduction 



^S€_^^.. -iL^-^ 



Applied anatomy 



The lacrimal drainage system consists of the following 
structures {Fig. 2.1): 

1. The puncta are located at the posterior edge of the lid 
margin, at the junction of the lash-betiring lateral five- 
sixths (pars ciliaris) and the non-ciliated medial one-sixth 
(pars lacrimalis) of each lid. Normally they face slightly 
posteriorly and can be inspected by everting the medial 
aspect of the lids. Treatment of excessive watering caused 
by punctal stenosis or malposition is relatively straight- 
forward. 

2. The canaliculi pass vertically from the lid margin (the 
ampullae) for about 2 mm. They then turn medially and 
run horizcmtally for about 8 mm to retich the lacrimal sac. 
The superior tuid inferior canaliculi most often unite to 
form the common canaliculus, which opens into the 
lateral wall of the lacrimal sac. In some individuals, each 




Ampuila (2 mm} 
Common canaliculiis ' 



Fig.ii 

Anatomy of the lacrimal drainage system 



Canaliculus (8 mm) 



Lacrimal 
sac (10 mm) 

Nasolacrimal 
duct (12 mm) 

Valve of Hasner 



canaliculus opens separately, A small flap of mucosa 
(valve of Rosenmullcr) overhangs the junction of the com- 
mon canaliculus and the lacrimal sac and prevents reflux 
of tears into the canaliculi. Treatment of canalicular 
obstruction is frequently complicated, 

3. The lacrimal sac is about 10 mm long and lies in the 
lacrimal fossa between the anterior and posterior lacrimal 
crests. The lacrimal bone and the frontal process of the 
maxilla separate the lacrimal sac from the middle meatus 
of the nasal cavity, hi a dacryocystorhinostomy (DCR) an 
anastomosis is created between the sac and the nasal 
mucosa to bypass an obstruction in the nasolacrimal duct. 

4. The nasolacrimal duct is about 1 2 mm long and is the 
inferior continuation of the lacrimal sac. It descends and 
angles slightly laterally and posteriorly to open into the 
inferior nasal meatus, lateral to and below the inferior 
turbinate. The opening of the duct is partially covered by a 
mucosal fold (valve of Blasner). (Jbstruction of the duel 
may cause a secondary distension of the sac. 

Applied physiology 



Tears secreted by the main and accessory lacrimal glands 
pass laterally across the ocuku- surface. A variable amount of 
the aqueous component of the tear film is lost by evaporation. 
This is related to the size of the palpebral aperture, the blink 
rate, ambient temperature and humidity. The remainder of 
the tears drain as follows (Fig. 2.2): 

1. Tears flow along the upper and lower marginal strips and 
enter the upper and lower canaliculi by capillarity and also 
possibly by suction. About 70% of tears drain through the 
lower canaliculus and the remainder through the upper 
(Fig. 2.2a). 

2 . With each blink, the prelarsal orbicularis oculi compresses 
the ampullae, shortens the horizontal canaliculi and 
moves the puncta medially (Fig. 2.2b). Simultaneously, the 
lacrimal part of the orbicuhrris oculi, which is attached to 
the fascia of the lacrimal sac, contracts and expands the 
sac, thereby creating a negative pressure which sucks the 
tears from the canahculi into the sac. 

3. When the eyes open the muscles relax, the sac collapses 
and a positive pressure is created which forces the tears 




Fig. 2.2 

Physiology of the lacrimal 
pump mechanism 



Lacrimal Drainage System 



45 



down the nasolacrimal duct into the nose (Fig. 2.2c]. 
Gravity also plays a role. The puncla move laterally, the 
canaliculi lengthen and fill with tears, 

Causes of watering 

Overflow ol" tears may represent lacrimation or epiphora. 

1. Lacrimation (hyper lacrimation) is caused by reflex 
lacrimal hypersecretion secondary to ocular inflammation 
or surface disease, hi these cases watering is associated 
with symptoms of the underlying cause and treatment is 
usually medical. 

2. Epiphora is due to compromise of lacrimal drainage. It is 
exacerbated by a cold and windy atmosphere, and is least 
in a warm dry room. It may be caused by: 

a. Malposition of the lacrimal puncta (e.g. secondary to 

ectropion). 
k Obstruction anyw^here along the lacrimal drainage 

system, from the puncta to the nasolacrimal duct, 
c. Lacrimal pump failure, which may occur secondarily 

to lower lid laxity or weakness of the orbicularis muscle 

(e.g. facial nerve palsy). 

^ Evaluation of the 
watering eye 

External examination 

I. The marginal tear strip of both eyes should be 
examined on the slit-lamp prior to any manipulation of 
the eyelids or instillation of topical medication, which may 
prejudice the clinical picture. Many patients with epiphora 
do not have obvious overflow of tears onto the face but 
merely show a high marginal tear strip on the affected 
side. 



The eyelids should be examined for evidence of mal- 
position. Perhaps the commonest cause of lid (and 
consequently puncta 1) malposition is ectropion, which 
may be of involutional, paralytic or cicatricial aetiology. 
Such ectropion may involve predominantly the pars 
lacrimalis. Normally the inferior lacrimal punctum is 
apposed to the globe and not visible without everting the 
lower lid. A rare cause of epiphora is the Centurioji 
syndromt. Patients with this condition manifest epiphora 
from childhood secondary to anterior malposition of the 
medial part of the lid with displacement of puncta out 
of the lacus lacrimalis due to a prominent nasal 
bridge (Fig. 2.3). Occasionally epiphora may be caused 
by a large caruncle displacing the inferior punctum 
away from the globe (Fig. 2.4) or obstruction of the 
inferior punctum by a fold of redundant conjunctiva 
(conjunctivochalasis). 

The dynamics of eyelid closure should be evaluated. 
Normally, the lid margins approximate and the puncta are 
apposed when the eyes close. In patients with low^er lid 
laxity, one lid may over-ride the other or the puncta may 
evert (Fig. 2.5). 




Fig. 2.4 

I Large caruncle displacing the inferior punctum 




Fig. 2.3 

Centurion syndrome 



Fig. 2.5 

Right upper lid over-riding the lower 




Clinical Ophthalmology 



4. The puncta are best examined on the slit-lamp. Apart 
from malposition, the puncta may be inflamed, stenosed 
(Fig. 2.6) or obstructed, sometimes by an eyelash 
(Fig, 2.7). Canaliculitis is characterized by pouting of the 




Fig. 2.6 

Punctal stenosis associated with mild ectropion 




Fig. 2.7 

Punctal obstruction by an eyelash 






Fig. 2,9 

Accessory punctum 




Fig. 2.8 

Pouting punctum in chronic canaliculitis 



Fig. 2.10 

Expression of mucopurulent material 



punctum (Fig. 2.8) and expression of pus or concretions 
on manual canalicular compression with a glass rod, 
Abnormal findings in children include punctal agenesis, 
accessory puncta (Fig. 2.9 ) or a congenital lacrimal fi.stula. 

5. The lacrimal sac should then be palpated. Punctal reflux 
of mucopurulent material on lacrimal compression 
(Fig. 2.10) is indicative of a mucocele with a patent 
canalicular system, but with an obstruction either at, or 
distal to, the lower end of the lacrimal sac. In acute dacry- 
ocystitis palpation is severely painful and compression 
should be avoided. Occasionally, palpation of the sac mil 
reveal a stone or a tumour. 

6. Fluorescein retention test (ffuorescein disappearance 
test) is performed by instifling fluorescein 2% drops into 
both conjunctival fornices. Normally, little or no dye 
reinains after 3 minutes, l^rolonged retention is indicative 
of inadequate lacrimal drainage and can be graded from 1 
to 4 (Fig. 2,11). 



Probing and irrigation 

This is performed only after ascertaining punctal patency. 
l^Inder topical anaesthesia, a gently curved, blunt tipped 



Lacrimal Drainage System 



41 







Fig. 2.11 

Prolonged retention of fluorescein-stained tears 





Fig. 2.1 2 

(a) Hard stop; (b) soft stop 



kcrimaJ cannula on a 2 ml saline-filled syringe is inserted into 
Ihe lower pLinctum and advanced, following tlie contour of the 
candiculus. An attempt is made to enter the lacrimal sac, the 
medial wall of which lies against the bone of the lacrimal fossa. 
The cannula can come either to a hard stop or to a soft stop. 

L A iiard stop occurs if the cannula enters the lacrimal sac. 
IL comes to a stop at the medial wall of the sac, through 
which can be felt the rigid lacrimal bone {Fig. 2.12a). This 
excludes complete obstruction of the canalicular system. 
The examiner places one finger over the lacrimal fossa and 
irrigates. If the saline passes into the nose the patient has 
a patent lacrimal drainage system, which may, however, 
be stenosed; alternatively there may be subtle lacrimal 
pump failure. Failure of saline to reach the nose is 
indicative of total obstruction of the nasolacrimal duct. In 
this situation, the lacrimal sac will become distended 
during irrigation and there will also be reflux through the 
upper punctum. The regurgitated material may be clear. 
mucoid, mucopurulent or frankly purulent, depending on 
the contents of the lacrimal sac. 

2. A soft stop is experienced if the cannula stops at or 
proximal to the junction of the common ctmahculus and 
the lacrimal sac, i.e. at the lateral wall of the sac. The sac 
is thus not entered- — a spongy feeling is experienced as the 
cannula presses the soft tissue of the common canaliculus 
and the lateral wall against the medial wall of the sac and 
the lacrimal bone behind it (Fig, 2.12b). Irrigation will 



therefore not cause the sac to distend. In the case of lower 
canalicular obstruction, there will be reflux of saline 
through the k)wer punctum.. Reflux through the upper 
punctum indicates patency of both upper and lower 
canaliculi, but obstruction of the common canaliculus. 

Jones dye testing 

This is only indicated in patients with suspected ptu-tial ob- 
struction of the drainage system. These patients manifest epi- 
phora, but the lacrimal system can be successfully syringe 
krigated. Dye testing is of no value in the context of total 
obstruction. 

I. The primary test (Fig. 2.13a) differentiates partial 
obstruction of the lacrimal passages from primary 
hypersecretion of tears. First, a drop of 2% fluorescein Is 
instilled into the conjunctival sac. After about 5 minutes, a 
cotton-tipped bud moistened in a local anaesthetic is 
inserted under the inferior turbinate at the nasolacrimal 
duct opening. The results are interpreted as follows: 

a. Positive: fluorescein recovered from the nose indicates 
patency of the drainage system. Watering is due to 
primary hypersecretion and no further tests are 
necessary. 

b. Negative: no dye recovered from the nose indicates a 
partial obstruction (site unknown) or failure of the 




Fig. 2.1 3 

Jones dye testing, (a) primary; (b) secondary 



48 



Clinical Ophthalmology 



lacrimal pump mechanism. In this situation the 
secondary dye test is performed immediately. 



NB: 22% of normal individuals manifest a negative 
primary Jones test. 


\ 


» -^ .■ -■ . . ' ■ ^ ■ ■ -T' 



2. The secondary (Irrigation) test (Fig. 2.13b) identifies 
the probable site of partial obslrucLion, on the basis of 
whether the topical fluorescein instilled for the primary 
test entered the lacrimal sac. Topical anaesthetic is 

instilled and any residual fluorescein washed out. The 
drainage system is then irrigated with saline with a 
cotton-tipped bud under the inferior turbinate. 
a. Positive: fluorescein-stained saline recovered Irom the 
nose indicates that fluorescein entered the lacrimal sac, 
thus confirming functional patency of the upper 
lacrimal passages. Partial obstruction of the naso- 
lacrimal duct is inferred. 
h. Negative: unstained saline recovered from the nose 
indicates that fluorescein did not enter the lacrimal sac. 
This implies partial obstruction of the upper lacrimal 
passages (puncta, canaliculi or common canaliculus) 
or a defective lacrimal pump mechanism. 

Contrast dacryocystography 

I. Technique 

a. The inferior puncta are dilated with a Nettleship 
punctum dilator. 

b. Plastic catheters are inserted into the inferior canaliculi 
on either side (alternatively the upper puncta may be 
used). 

c. Contrast medium, usually 1 ml of Lipiodol, is simul- 
taneously injected on both sides and postero-anterior 
radiographs are taken (Figs 2.14, 2.1 5). 

d. Five minutes later an erect oblique film is taken to assess 
the effect of gravity on tear drainage. 




Fig. 2.14 

Right dacryocystogram showing free flow of contrast medium 
into tiie nose despite mild stenosis of the common canaliculus 
(Courtesy of R. Wet ham) 




Fig. 2.1 5 

Bilateral dacryocystogram. (Right) shows some irregularity of 
the common canaliculus, although contrast medium passes 
through an otherwise patent lacrimal system; (left) shows 
complete obstruction high in the sac (Courtesy of R. Weiham) 



2. Interpretation. Failure of dye to reach the nose indicates 
an anatomical obstruction, the site of which is usually 
evident. A normal dacryocystogram in the presence of 
epiphora indicates either partiEil obstruction or lacrimal 
pump failure. Dacryocystography is also helpful in the 
diagnosis of diverticula, fistulae and filling defects caused 
by stones or tumours. 

Lacrimal scintillography 

This is a sophisticated test which assesses tear drainage under 
more physiological conditions than dacryocystography. 
Although it does not provide the same detailed anatomical 
visualization as dacryocystography, it is more sensitive in 
assessing incomplete blocks, especially in the upper part of 
the lacrimal system. The test is performed as follows: 

a. Radionuclide technetium-99 is delivered by a micropipette 
to the lateral conjunctival sac as a 1 ^.1 drop. The tears are 
thus labelled with this gamma-emitting radioactive 
substance. 

b. The tracer is imaged by a gamma camera focused on the 
inner canthus and a sequence of images is recorded over 
20 minutes, 



Obstruction of lacrimal 
drainage 




Acquired obstruction 



Primary punctal stenosis 

This occurs in the absence of punctal eversion. 



Lacrimal Drainage System 



49 



1. Causes ~r 

• Idiopcithic primary stenosis is hj far the most common . 

• Herpes simplex lid infection. 

• following irradiation of malignant lid tumours. 

• Cicatrizing conjunctivitis and trachoma. 

• Systemic cytotoxic drugs such as 5-tluorouracil and 
docetaxel. 

2. Treatment is initially by dilatation of the punctum with a 
Netlleship dilator (Fig. 2.16). If repeated dilalation is 
unsuccessful one of the following procedures may be 
considered: 

«. One'Snip ampiiUotouiij, in which a vertical 2 mm snip 
is made in the posterior wall of the ampulla, 

/). Two-snip procedure in which both a vertical and a 
small htirizontal cut is made in the ampulla (Fig. 2.1 7). 
I'his yields a larger (Fig. 2.18) and more permanent 
opening than a one-snip procedure. 

('. Lnscr pumtoplasty in which the punctum is opened 
with an argon laser. This method is particularly useful 
in elderly patients in whom the punctum is occluded by 
an overgrowth of conjunctival epithelium. 

d. Insertion of canalized plu0S into the inferior punctum. 




Jiiar^JVf ^/f//ffiVffV/tfiUifi/f'^J//f/flf^f3$f 




Fig. 2.16 

Tectinique of dilating the inferior punctum 



Fig. 2.18 

Appearance following a two-snip procedure 



Secondary punctai stenosis 

This occurs secondary to punctai eversion {sei' Fig. 2.6). 
Treatment of pure punctai eversion, unassociated with 
significant involutional ectropion, is by one of the following: 

a. Ziegler cautery burns are applied to the palpebral 
conjunctiva, 5 mm below the punctum. Subsequent 
shrinkage of the cauterized tissue (cicatrization) should 
invert the punctum. 

b. Medial coiijunctivoplastii involves excision of a dicunond- 
shaped piece of tarsoconjunctiva, about 4 mm high cind 8 
mm wide, parallel with and inferior to the canaliculus and 
punctum, followed by approximation of the superior and 
inferior wound margins with sutures (Fig. 2.19). Incor- 
poration of the lower lid retractors in the sutures further aids 
punctai inversion. Once the punctum is restored to its 
normal position, it is dilated so that it may remain open when 
normal tear flow is established. If stenosis recurs, treatment 
is the sfmie as for primary stenosis. 





...^ 




"irrr 



Fig. 2.17 

Two-snip procedure for punctai stenosis, (a) Vertical cut; 
(b) horizontal cut; (c) final result 



Canalicuiar obstruction 

I . Causes are similar to those of primary punctai obstruc- 
tion. 




Fig. 2.19 

Medial conjunctivoplasty 



w 



Clinical Ophthalmology 



2. Treatment depends on the site and degree of obstruction. 
a. Partial obstruction of the common or individual 
canaliculi, or indeed anywhere in the nasolacrimal 
drainage system, may be treated by intubation. Two 
ends of a length of silicone tubing are threaded via the 
superior and inferior puncta, through the lacrimal sac 
down to the nose, where they are tied (or secured with 
a special (Watzke) sleeve) and left in situ for 3-6 months 
(Fig. 2.20). 
h. Total individual canalicular obstruction, with at least 
8 mm of patent normal canaliculus between the 
punctum and obstruction, is treated by anastomosis 
of the patent part of the canaliculus into the lacrimal 
sac (canaliculodacryocystorhinostomy — CDCR) and 
intubation. When the block is less than 8 mm from the 
punctum treatment involves conjunctivodacryocysto- 
rhinostomy and the insertion of a special (Lester Jones) 
tube {see below). 

c. Total obstruction of the lateral end of the common 
canaUculus is usually caused by idiopathic peri- 
canalicular fibrosis, in which the entire common 
canaliculus is obstructed. Dacryocystography will 
obviously show failure of filling of the common 
canaliculus. Treatment involves resection of the 
obstructed common canaliculus and CDCR. The 
lacrimal system is then intubated for i-6 months. 

d. Total obstruction of the medial end of the common 
canaliculus is often caused by a thin membrane at its 
junction with the lumeu of the sac, often secondtiry to 
chronic dacryocystitis. Dacryocystography will show 
Klling of the common canaliculus. This is treated by 
OCR and excision of the membrane from its sac aspect 
(see below). The lacrimal system is then intubated for 
3-6 months. 



• Wegener grfmulomatosis. 

• Infillralion by nasopharyngeal tumours. 

2. Treatment depends on the completeness of obstruction 

as follows: 

a. Complete obstruction is treated by DCR. 

h. Incomplete obstruction may respond to intubation of 
the lacrimal system with silicone tubes or stents. This 
should only be performed if the tubes or stents can 
be passed easily, otherwise a DCR should be done. Some 
cases may benefit from balloon dilatation {see below). 

Dacryolithiasis 

Dacryoliths (lacrimal stones) may occur in any part of the 
lacrimal system, more commonly in males. Although the 
pathogenesis is unclear, it has been proposed that tear 
stagnation secondary to inflammatory obstruction may 
precipitate dacryolith formation and squamous metaplasia of 
the lacrimal sac epithelium. 

1. Presentation 

• Dacryoliths are often asymptomatic and may be 
discovered at the time of DCR. 

• Symptomatic patients usually present in late adulthood 
in a variety of ways including intermittent epiphora, 
recurrent attacks of acute dacryocystitis and lacrimal 
sac distension. 

2. Signs 

• The lacrimal sac is distended and relatively firm, but is 
not inflamed and tender as in acute dacryocystitis. 

• Mucus reflux on pressure may or may not be present, 

3. Treatment involves massage, lacrimal irrigation and 
probing; DCR may be required for complete obstruction. 



Congenital obstruction 



Nasolacrimal duct obstruction 

\. Causes 

• Idiopathic stenosis is by far the most common. 

• Naso-orbital trauma. 




Nasolacrimal duct obstruction 

This is perhaps better termed delayed canalization of the 
nasolacrimal duct, since it often resolves spontaneously The 
lower end of the nasolacrimal duct (at the valve of Hasner) is 
the last portion of the lacrimal drainage system to canalize, 
complete canalization usually occurring soon after birth. 
However, up to 20% of children manifest evidence of naso- 
lacrimal obstruction in the first year of life. 

1. Signs 

■ Epiphora and matting of lashes may be constant or 
intermittent when the child has a cold or upper 
respiratory tract infection (Fig. 2.21). 

• Gentle pressure over the lacrimal sac causes reflux of 
purulent material from the puncta. 

• Acute dacryocystitis is uncommon (Fig. 2.22). 

2. Differential diagnosis of other congenital causes of a 
watering eye include punctal atresia and fistulae between 
the sac and skin. 



Fig. 2.20 

Silicone tube in situ 



NB: It is important to exclude congenital glaucoma in an 
infant with a watering eye. 



Lacrimal Drainage System 



51 




Fig. 2.21 

Sticky eye due to delayed canafization of the nasolacrimal duct 




Fig. 2.22 

Acute dacryocystitis secondary to cJelayed canalization of the 

nasolacrimal duct (Courtesy of R. Welham) 



a 


b 


--\ 






X, 


>• „. . X 






4, 




Fig. 2.23 

Technique of probing of the nasofacrimal duct 



antibiotic drops are used q.i.d. for 1 week. If, after 6 weelcs, 
, there is no improvement, probing sliould be repeated, 
Nasal endoscopic monitoring of probing is recommended, 
especially for repeated probing, to detect anatomical 
abtiormalities and ensure correct probe position. 
4. Results. Ninety per cent of children are cured by the first 
probing and a further 6% by the second. Failure is usually 
the result of abnormal anatomy, which can usually be 
recognized by difficulty in passing the probe and subse- 
quent non-patency of the lacrimal drainage system on 
irrigation. If symptoms persist despite two technically 
satisfactory probings, temporary intubation with fine 
silastic tubes or balloon dilatation of the nasolacrimal duct 
may effect a cure. Patients who fail to respond to such 
measures can be treated with DCR performed between the 
ages of 3 and 4 years, provided the obstruction is distal to 
the lacrimal sac. 



3. Treatment 

fl. Mttssflffc of the lacrimal sac increases the hydrostatic 
pressure and may rupture the membranous obstruction. 
In performing this manoeuvre, the index finger is placed 
over the common canaliculus to block reflux through the 
puncta and then massaged firmly downwards. Ten strokes 
should be applied four times a day Massage should be 
accompanied by lid hygiene; however, topical antibiotics 
should be reserved for superadded bacterial conjunc- 
tivitis, which is surprisingly uncommon. 

b. ?roh'mQ of the lacrimal system should be delayed until 
the age of 12 months because spontaneous canaliza- 
tion occurs in about 95% of cases. Probing performed 
within Xht first 2 years of life has a very high success 
rate, but thereafter the efficacy decreases. It should be 
carried out under a general anaesthetic and preferably 
through the upper punctum (Fig. 2.23). The rationale 
is to manually overcome the obstructive membrane at 
the Hasner valve. After probing, the lacrimal system is 
irrigated with saline labelled with fluorescein. If 
lluorescein can be recovered by aspiration from the 
pharynx, successful probing is confirmed. Postoperative 




Fig. 2.24 

Amniontocele (Courtesy of R. Welham) 




52 



Clinical Ophthalmology 



Congenital dacryocele 

A congenital dacryocele (amniontocele) is a collection of 
amniotic fluid or mucus in the lacrimal sac caused by an 
imperforate Hasner valve. 

1 . Presentation is perinatal with a bluish cystic swelling at 
or below the medial canthal area, accompanied by 
epiphora (Fig. 2.24). 

2. Signs. A tense lacrimal sac which is initially filled with 
mucus but may become secondarily infected. 



^B: It should not be mistaken for an encephaloceie,L_S 
which is characterized by a pulsatile swelling above the 
medial canthal tendon. 



3. Treatment is initially conservative but if this I'ails probing 
should not be delayed. 

Principles of lacrimal surgery 



Conventional DCR 

This is indicated for obstruction beyond the media! opening of 
the common ctmtiliculus (i.e. the canalicular system is patent). 
In principle this operation involves anastomosing the lacrimal 
sac to the nasal mucosa of the middle nasal meatus. The 
procedure is performed under general hypotensive anaesthesia. 

I. Technique 

a. The middle nasal mucosa is packed with sterile ribbon 
gauze soaked in 2% lignocaine with 1 ;20(),000 adrena- 
line, to achieve vasoconstriction of the mucosa. 

b- A straight vertical incision is made 10 mm medial to the 
inner canthus, avoiding the angular vein (Fig. 2.25a). 



c. The anterior lacrimal crest is exposed by blunt 
dissection and the .superficial portion of the medial 
palpebral ligament divided. 

d. The periosteum is divided from the spine on the anterior 
lacrimal crest to the fundus of the sac and reflected 
forwards. The sac is reflected laterally from the lacrimal 
fossa (Fig. 2.25b). 

e. The anterior lacrimal crest and the bone from the 
lacrimal fossa are removed (Fig. 2.2 5c). 

f. A probe is introduced into the lacrimal sac through the 
lower canaliculus and the sac is incised in an 
'H-shaped' manner to create two flaps. 

g. A v^ertical incision is made in the nasal mucosa to create 
anterior and posterior flaps (Fig. 2.2 5d). 

h, The posterior flaps are sutured (Fig. 2.25e). 
i. The anterior flaps are sutured (Fig. 2.2 5f). 
j. The medial canthal tendon is resutured to the peri- 
osteum and the skin incision closed with interrupted 
sutures. 
Results in experienced hands are exceUent with a success 
rate of over 90'Ki. 

Causes of failure include inadequate size and position of 
the ostium, unrecognized common canaficular obstruc- 
tion, scarring and the 'sump syndrome', in which the 
surgical opening in the lacrimal bone is too smaU and too 
high. There is thus a dilated lacrimal sac lateral to toid 
below the level of the inferior margin of the ostium, in 
which secretions collect, unable to gain access to the 
ostium and thence the nasal cavity. 
Potential complications include cutaneous scarring, 
injury to medial canthal structures, haemorrhage, 
cellulitis and cerebrospinal fluid rhinorrhoea, if the 
subarachnoid space is uiadvertentl}^ entered. 




Fig. 2.25 

Technique of dacryocystorhinostomy (see text) 



Lacrimal Drainage System 



53 



Endoscopic DCR 

This may be considered for obstruction beyond the medial 
opening of the common canaliculus, particularly following 
failed conventional DCR. The procedure can be performed 
cither under general anaesthesia (without hypotension) or 
local anaesthesia. Advantages over conventional DCR 
include the lack of skin incision, shorter operating time, 
lower risk of interfering with the physiological lacrimal pump 
mechanism, minimal blood loss and no risk of cerebrospinal 
lluid rhinorrhoea. 

1. Technique, A slender light pipe is passed through the 
lacrimal puncta and canaliculi into the lacrimal sac 
and viewed from within the nasal cavity with an 
endoscope. The remainder of the procedure is performed 
from viithin the nasal cavity. 

a. The mucosa over the frontal process of the maxilla is 
stripped. 

b. A part of the nasal process of the maxilla is removed. 

c. The lacrimal bone is broken off piecemeal. 

d. The lacrimal sac is opened. 

e. Silicone tubes are passed through the upper and lower 
puncta, pulled out through the ostium and tied within 
the nose, 

2. Results. The success rate is about 8 5%. 



Endofaser DCR 

Performed with a holmium:YAG laser, this is a quick 
procedure which can be carried out under local anaesthesia. 
It is tbcrefore ptirticularly suitable for elderly patients. The 
success rate is only about 70% but because normal anatomy 
is not disrupted it does not prejudice subsequent surgical 
intervention in the cases that fail. 



Lester Jones tube 

Insertion of a Lester Jones tube is indicated when there is 
absence of canalicular function, either due to obstruction 
k'ss than 8 mm from the puncta, or due to lacrimal pump 

failure. 

a. A DCR is performed as far as suturing the posterior 
flaps. 

b. The caruncle is partially excised. 

c. A slab incision is made with a Graefe knife from a point 
about 2 mm behind the inner canthus (under the former 
caruncle) in a medial direction, so that the tip of the knife 
emerges just behind the anterior Ilap of the lacrimal sac 
(Fig. 2.26a). 

d. The tract is enlarged sufficiently with a microtrephine to 
allow the introduction of a polythene tube (Fig. 2.26b). 

e. The incision is sutured as for a DCR. 

r After 2 weeks the polythene tube is replaced by a glass 
tube. 





Fig. 2.26 

Technique of Lester Jones tube insertion (see text) 

Balloon dacryocystophsty 

This may be a satisfactory primary treatment for adults with 
partial nasolacrimal duct obstruction who do not exhibit 
signs of chronic infection. 

Infections of lacrimal 
passages 

Chronic canaliculitis 

Chronic canaliculitis is an uncommon condition, frequently 
caused by Actinomijces, which tire anaerobic Gram-positive 
bacteria. While a diverticulum or obstruction of the canaliculus 
can promote anaerobic bacterial growth secondary to stasis, in 
most cases there is no identifiable predisposition. 

1 . Presentation is with unilateral epiphora associated with 
chronic mucopurulent conjunctivitis, refractory to 
conventional treatment. 

2. Signs 

• Pericanalicular inflammation is characterized by 
oedema of the canaliculus (Fig. 2.27) and a *pouting' 
punctum best seen with the sUt-lamp (Fig. 2.28). 

• Concretions consisthig of sulphur granules are expressed 
on canalicular compression with a glass rod (Fig. 2.29). 



JVB: In contrast to dacryocystitis, there is no 
nasolacrimal duct obstruction, lacrimal sac distension or 
inflammation. 



3. Treatment 

a. Topical antibiotics such as ciprofloxacin q.i.d, for 
10 days may be tried initially but iure rareljr curative. 



S4 



Clinical Ophthalmology 




Fig. 2.27 

Oedema of the left upper canaliculus in chronic canaliculltis 





Fig. 2.28 

Pouting of the punctum in chronic canaliculltis 



Fig, 2.30 

Exposure of large concretions following canaliculotomy in 
chronic canaliculltis 



Dacryocystitis 



Infection of the lacrimal sac is usually secondary to 
obstruction of the nasolacrimal duct. It may be acute or 
chronic and is most commonly caused by staphylococci. 

Acute dacryocystitis 

I . Presentation is with subacute onset of pain, redness and 
swelling at the medial can thus and epiphora. 






Fig. 2.29 

Expressed concretions in chronic canaliculltis 



h. Canaliculotomy (Fig. 2.30) involving a linetir incision 
into the conjunctival side of the canaliculus is the 
most effective treatment, although occasionally it may 
result in scarring and interference with canalicular 
function. 



Fig. 2.31 

Acute dacryocystitis 



Lacrimal Drainage System 



SS 



2. Signs, A very lender, red. tense swelling at the medial 
ciinlhus which may be associated with preseptal cellulitis 
in severe cases (Fig. 2.31). 

3. Treatment 

f(. liiUid! treatment involves the application of local 
vviirmth and ored antibiotics such as flucloxaciliin. 



NB: Irrigation and probing should not be performed. 




b, incision and drainage. The infection may sometimes 
extend outside the sac to produce an abscess in the 
perilacrimal soft tissue (lacrimal abscess). If pus 
points and the abscess threatens to drain 
spontaneoLTsly (Fig. 2.32), incision and drainage may 
be considered. This, however, carries a risk of llie 
development of a lacrimal fistula, which may serve as 




Fig. 2.33 

Mucocele 



ifp-- 



II 




Fig. 2.32 

Lacrimal sac abscess 



a conduit for tears from the lumen of the lacrimal sac 
to the skin surface. 
c. DCR is usually necessary after the acute infection has 
been controlled and should not be delayed because of 
the risk of recurrent infection. 

Chronic dacryocYstitis 

1 . Presentation is with epiphora which may be associated 
with a cfn:(mic or recurrent unilateral conjunctivitis. 

2. Signs. A painless swelling at the inner canthus caused by 
a mucocele (Fig. 2.3 3). Obvious swelling may be absent, 
although pressure over tfie sac commonly still results in 
reflux of mucopurulent material tiirough the canaliculi 
{see ¥\g. 2.10). 



JVB: It is often wise to postpone intraocular surgery | \^ 
until lacrimal infection has been treated, owing to the grave 
risk of endophthalmitis. 



3. Treatment is with DCR. 



CHAPTER 



3 



The Dry Eye 



Applied physiology 57 
Causes 57 
Clinical features 58 
Special investigations 59 

Treatment 60 



56 



The Dry Eye 



57 



Applied physiology 



The main lacrimal glands produce about 95% of the aqueous 
component of tears and the accessory lacrimal glands of 
Krause and Wolfring produce the remainder. Secretion of 
tears has basic (resting) and much greater reflex com- 
ponents. Reflex secretion occurs in response to corneal and 
conjunctival sensory stimulation, tear break-up and dry spot 
formation or ocular inflammation. It is reduced by topical 
anaesthesia. Although in the past basic secretion was 
ascribed to the accessory lacrimal glands and reflex secretion 
to the main lacrimal glands, it is now thought that the whole 
mass of lacrimal tissue responds as one unit. The precorneal 
lear film consists of three layers: (a) lipid, (b) aqueous and 
(e) mucin, each of which has separate functions (Fig, 3.1). 

Outer tipid layer 

This is secreted by the meibomian glands. 

1. Functions 

• To retard evaporation of the aqueous layer of the tear 
film, 

• To lower surface tension of the tear film. This, in turn, 
draws water into the tear film and thickens the aqueous 
layer. 

• To lubricate the eyeUds as they pass over the surface of 
the globe. 

2. Dysfunction of this layer may result in an evaporative dry 
i'tn: 

Niiddfe aqueous layer 

This is secreted by the lacrimal glands and consists of 
proteins, electrolytes and water. 

I. Functions 

• To supply atmospheric oxygen to the avascular corneal 
epithelium. 




• Antibacterial function due to the presence of tear 
proteins such as IgA. lysozyme and lactoferrin. 

• To abolish any minute irregularities of the anterior 
corneal surface. 

• To wash away debris and noxious stimuli and allow the 
passage of leucocytes after injury. 

2. Deficiency of this layer results in a hyposecretive dry eye. 

Inner mucin iayer 

This is secreted by the conjunctival goblet cells, the crypts of 
Henle and the glands of Manz. 

1 . Function 

• Wetting of the cornea by converting the cornea] 
epithelium from a hydrophobic to a hydrophilic surface 
(Fig. 3.2. right). 

• Lubrication. 

2. Deficiency of this layer may be a feature of both 
hyposecretive and evaporative states (Fig. 3.2, left). 

The tear fdm is mechanically spread over the ocular surface 
through a neuron ally controlled blinking mechanism and 
after a period of time is cleared through the nasolacrimal 
drainage system. The three factors required for effective 
resurfacing of the tear film are; (a) normal blink reflex, 

(b) concjnuty between the external ocular surface and eyelids and 

(c) normal corneal epithelium. 

Causes 



The terms 'dry eye' and 'keratoconjunctivitis sicca' (KCS) are 
synonymous. The two main categories are: (a) hyposecretive, 
which may be Sjogren or non-Sjogren, and (b) evaporative, 
although the two are not mutually exclusive. 



Microvillus 




Epithelial cell 




Fig. 3.1 

The three layers of the precorneal tear film 



Fig. 3.2 

Function of the mucin layen (Left) in mucin deficiency, the 
aqueous layer (blue) cannot wet the corneal epithelium; 
(right) a normal amount of mucin (red) enables wetting of the 
corneal epithelium by the aqueous layer 



58 



Clinical Ophthalmology 



Sjogren hyposecretive KCS 

Sjogren syndrome Is a cytokine and rect-ptor-mediated 
infltuiimatory process that affects the lacrimal gland acini 
and ducts, leading to abnormalities in the tear film with 
resultant ocular surface disease, 

1. Primary Sjogren syndrome is chciracteriaed hy a dry 
mouth (xerostomia) and the presence of antibodies 
indicative of autoimmune pathcjgenesis. 

2. Secondary Sjogren is characterized by a systemic 
autoimmune connective tissue disorder such as 
rheumatoid arthritis, systemic lupus erythematosus, 
systemic sclerosis, dermatomyositis and polymyositis, 
mixed connective tisstie disease, relapsing polychondritis 
or primary bihary cirrhosis, in addition to the features of 
primary Sjogren syndrome. 

Non-Siogren KCS 

1 . Primary age-retated is the most common. 

2. Destruction of lacrimal tissue by tumour or inflam- 
mation (e.g. pseudotumour, thyroid eye disease and 
sarcoidosis). 

3. Absence of the lacrimal gland following surgical 
removal; rarely congenital. 

4. Obstruction of ductules of the lacrimal gland as a result 
of severe conjunctival scarring (e.g. cicatricial pemphigoid 
and trachoma). 

5. Neurological lesions such as familial dysautonomia 
(Riley-Day syndrome). 

Evaporative KCS 

1. Oil deficiency is most frequently secondary to ob- 
structive meibomian gland dysfunction (see Chap- 
ter 1). 

2. Defective resurfacing of the eye by the tear film as a 
result of abnormal lid-globe congruity or defective 
blinking. 



Clinical features 

Symptoms 

The most common are irritation, foreign body sensation, 
burning, a stringy mucus discharge and transient blurring of 
vision. Less frequent symptoms include itching, photophobia 
and a tired or heavy feeling, l^atients with filamentary 
keratitis (see below) may complain of severe pain brought on 
by blinking. Surprisingly, patients seldom complain that their 
eyes are dry, although some may report a lack of emotional 
tears or a deficient response when peeling onions. The 
symptoms of KCS arc frequently exacerbated on exposure to 
conditions associated with increased tear evaporation (e.g. 
air-conditioning, wind, central heating) or prolonged 
reading, when blink frequency is reduced. Symptoms may be 
improved by lid closure. 



Tear film abnormalities 

1 . Mucus strands and debris are an early sign. In the 
norma! eye, as the tear film breaks down, the mucin layer 
becomes contaminated with lipid but is washed away. In 
the dry eye, the lipid-contarainated mucin accumulates in 
the tear film and tends to move with each blink. Mucin 
also has the interesting property of drying very quickly 
and rehydrating very slowly. 

2. The marginal tear meniscus is a crude measure of the 
volume of aqueous in the teiir film. The normal meniscus 
varies in height between 0.1 and 0.5 mm and forms a 
convex band with a regular upper edge. In KCS the tear 
meniscus becomes concave, irregular, thin (Fig. 3.3) or 
absent. 

3. Froth in the tear film or along the eyelid margin occurs in 
meibomian gland dj^sfunction (swFig. 1.3 3). 




Fig. 3.3 

Inferior punctate epithelial erosions stained with fluorescein 
and a thin marginal tear meniscus in keratoconjunctivitis sicca 



>^.,f;.,:. 


I^^^^^^^^^^HhI^^' 


i 


i 'iH^^^I 


^^H 


1 




^H 


7 




^^^ 





Fig. 3.4 

Corneal filaments 



The Dry Eye 



59 



KeFotopathy 

I, Punctate epithelial erosions involve the inferior cornea 

(sec Fig. }.3). 

I Filaments consist of small, comma-shaped mucus strands 
lined with epithelium attached at one end to the corneal 
surface (Fig. 3.4); the unattached end moves with each blink. 

3. Mucus plaques consist of semi-transparent, whitc-to- 
grey, slightly elevated lesions of various sizes and shapes. 
They ;ire composed of mucus, epithelial cells and protein- 
accoLis and lipoidal material. They are usually seen in 
association with corneal filaments and both stain with 
rose bengal (Fig. 3.5). 



i\lf; It should be remembered that a dry eye p red is poses |_^ 
to bacterial keratitis and sterile ulceration, which may lead 
to perforation (Fig, 3.6). 




Fig, 3.7 

A dry spot caused by tear film break-u[ 



Special investigations 



Tear fiim break-up time 

The tear lilm break-up time (BUT) is an index of precorneal 
teHrlilm stability. It is measured as follows: 




Fig. 3.5 

Mucus plaques and a few filaments stained with rose bengal 



a. Fluorescein is instilled into the lower fornix. 

b. The patient is asked to blink several times and then 
stop. 

c. The tear film is examined with a broad beam and a 
cobalt blue filter. After an interval of time, black spots 
or lines indicating the formation of dry areas will appear 
(Fig. 3.7). 

The BUT is the interval between the last blink and the 
appearance of the first randomly distributed dry spot. The 
development of dry spots alw^ays in the same location should 
be ignored because this is caused by a local corneal surface 
abnormality and not by intrinsic instability of the tear film. A 
BUT of less than 1 seconds is abnormal. 

Rose bengal 

This dye has an affinity for dead or devitalized epithelial cells 
and mucus. It stains the exposed bulbar conjunctiva, resulting 
in the typical staining pattern of two triangles with their bases 
at the limbus (Figs 3.8 and 3.9). Corneal lilaments and 
plaques are also shown up more clearly by the dye. One 
disadvantage of rose bengal is that it may cause ocular 




Fig. 3,6 

(a) Corneal perforation jn severe keratocoHiuncuvitis S4cca, (b) same eye stained with ftuarescein 



Clinical OphtKalmology 





Fig. 3.8 

Mild staining with rose bengal 




Fig. 3.9 

Extensive staining with rose bengal 



' :«S'<*i«SW»S5%;^j^MA'.'='4''^5^¥»M«VC'WA^t«9»*«¥K>'B*.<^/'*^>J* 



irritation which can last for up to a day, particularly in 
severely dry eyes. To minimize irritation a very small drop 
should be used, but a topical anaesthetic should not be used 
before instillation because it may induce a false-positive result. 

Schirmer test 

This is useful when aqueous deficiency is suspected in the 
absence of slit-lamp signs of KCS. The test involves measuring 
the amount of wetting of a special (no. 41 Whatman) filter 
paper, 5 mm wide and 3 5 mm long. The test can be performed 
with or without topical anaesthesia. In theory, when 
performed without an anaesthetic (Schirmer 1) it measures 
total secretion, basic and retlex, whereas with an anaesthetic 
(Schirmer 2) it measures only basic secretion. In practice, 
however, topical anaesthesia reduces reflex secretion but does 
not abolish it completely. The test is performed as follows: 

a. The eye is gently dried. 

b. The filter paper is folded 5 mm from one end and inserted 
at the junction of the middle and outer third of the lower 
lid, taldng care not to touch the cornea. 




Fig. 3.10 

Schirmer test 



c. The patient is asked to keep the eyes open and to blink 
normally (Fig. 3.10). 

d. After 5 minutes the filter paper is removed and the amount 
of wetting measured. 

A normal result is over 15 mm without anaesthesia and 
slightly less with anaesthesia. Between 6 and 10 mm is 
borderline and less than 6 mm indicates impaired secretion. 

Treatment 

The main aims of treatment of KCS are to relieve dis- 
comfort, provide a smooth optical surface and prevent 
structural corneal damage. One or more of the following 
measures may be used simultaneously. 

Preservation of existing tears 

1. Reduction of room temperature, by avoiding cenlral 
heating, to minimize evaporation of tears. 

2. Room humidifiers may be tried but are frequently 
disappointing because the apparatus is incapable of 
signiiicantly increasing the relative humidity of an 
average-sized room. A temporary local increase in 
humidity can be achieved with moist chamber goggles. 

3. A small lateral tarsorrhaphy which decreases the 
surface area of the interpalpebral fissure may be help- 
ful. 

Tear substitutes ' [ 

I. Drops 

• Hypromellose (Isopto Plain, Isopto Alkaline, lV;irs 
Naturale). 

• Polyvinyl alc'ohol (Hypotears. Liquitilm Tears, Snotears). k 

• Sodium hyaluronate (VLSMED, VISLUBE). ' 



The Dry Eye 



61 



Sodium chloride {Normasol, Steripod Blue). 

Povidone (Oculotet). 



NB.'The main disadvantages of drops are short duration _X 
of action and the development of sensitivity to the 
preservative (e.g. benzalkonium chloride, thiomersai). The 
latter can be avoided by using a preservative-free 
preparation (Minims). 



2. Gels (Viscoteara, GcJ Tears) consist of carboraers. In 
general, they are preferable to drops because they are 
instilled less frequently. 

3. Ointments containing petrolatum mineral oil (Lacri- 
Liibe, Lubri-Tears) can be used at bedtime. 

Muco/ytic agents 

Acetylcysteine 5% drops (Ilube) may be useful in patients 
with corneal filaments and mucous plaques. They are used 
q.i.d. and may cause irritation follov^^ing instillation. 
Acetylcysteine is also malodorous and has a limited bottle Me, 
so that it can only be used for up to 2 weeks. 

Reduction of tear drainage 

Punctal occlusion preserves natural tears and prolongs the 
effect of artificial tears. It is of greatest value in patients with 
severe KCS, particularly w?hen associated with toxicity from 
preservatives. 

1. Temporary occlusion of the puncta can be achieved by 
inserting commercially available collagen plugs into the 
canaliculi. The main aim of temporary occlusion is to 
ensure that epiphora does not occur following permanent 
occlusion. Initially all four puncta are occluded and the 
patient is reviewed after 1 week. If epiphora is induced, the 
upper plugs are removed and the patient is re-examined 
1 week later. If the patient is now asymptomatic, the plugs 
are removed and the inferior canaliculi are permanently 
occluded. Temporary occlusion can also be performed 
with the argon laser. 

2. Reversible long-term occlusion lasting several months 
can be achieved with silicone plugs. Potential problems 
include extrusion, granuloma formation and distal 
migration causing inflammation. 




Fig. 3.11 

Permanent punctal occlusion 



>»•>-■■. /.KvSW^-»»vj>,jK*;k'^vA-; *SSS>WB5«'.«i»:«!!S«5i«W»<a!!^ 



3. Permanent occlusion should be undertaken only in 
patients with severe KCS and repeated Schirmer test values 
of 2 mm or less. It should not be performed in patients who 
develop epiphora following temporary occlusion of only 
the inferior puncta. Permanent occlusion should also be 
avoided in young patients as their tear production tends to 
fluctuate. Permanent occlusion is achieved by vigorous 
punctal dilatation followed by heating for 1 second the 
mucosal lining of the proximal canahculus with gentle 
cautery (Fig. 3.11). Following successful punctal occlu- 
sion, it is important to watch for signs of recanaliza- 
tion. It is also important to treat any associated disorder 
such as chronic blepharitis and superinfection before 
occlusion. 

Other options 

1 . Topical cylosporin (0.05%, 0.1%) is a safe, well-tolerated 
and effective new medication which reduces cell-mediated 
inflammation of lacrimal tissue. 

2. Oral cholinergic agents such as pilocarpine (Salagan) 
are very effective in the relief of xerostomia and about 
40% of KCS patients also obtain relief.